Construction and validation of a simplified fracture risk assessment tool for Canadian women and men: results from the CaMos and Manitoba cohorts
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A procedure for creating a simplified version of fracture risk assessment tool (FRAX®) is described. Calibration, fracture prediction, and concordance were compared with the full FRAX tool using two large, complementary Canadian datasets.
The Canadian Association of Radiologists and Osteoporosis Canada (CAROC) system for fracture risk assessment is based upon sex, age, bone mineral density (BMD), prior fragility fracture, and glucocorticoid use. CAROC does not require computer or web access, and categorizes 10-year major osteoporotic fracture risk as low (<10%), moderate (10–20%), or high (>20%).
Basal CAROC fracture risk tables (by age, sex, and femoral neck BMD) were constructed from Canadian FRAX probabilities for major osteoporotic fractures (adjusted for prevalent clinical risk factors). We assessed categorization and fracture prediction with the updated CAROC system in the CaMos and Manitoba BMD cohorts.
The new CAROC system demonstrated high concordance with the Canadian FRAX tool for risk category in both the CaMos and Manitoba cohorts (89% and 88%). Ten-year fracture outcomes in CaMos and Manitoba BMD cohorts showed good discrimination and calibration for both CAROC (6.1–6.5% in low-risk, 13.5–14.6% in moderate-risk, and 22.3–29.1% in high-risk individuals) and FRAX (6.1–6.6% in low-risk, 14.4–16.1% in moderate-risk, and 23.4–31.0% in high-risk individuals). Reclassification from the CAROC risk category to a different risk category under FRAX occurred in <5% for low-risk, 20–24% for moderate-risk, and 27–30% for high-risk individuals. Reclassified individuals had 10-year fracture outcomes that were still within or close to the original nominal-risk range..
The new CAROC system is well calibrated to the Canadian population and shows a high degree of concordance with the Canadian FRAX tool. The CAROC system provides s a simple alternative when it is not feasible to use the full Canadian FRAX tool.
KeywordsBone mineral density Canada CAROC Fracture risk prediction FRAX Osteoporosis
We would like to thank Ms. Helena Johansson and Dr. John Kanis for their generating the Canadian FRAX results for both the CaMos and Manitoba cohorts. We thank all those participants in CaMos whose careful responses and attendance made this analysis possible. The authors are indebted to Manitoba Health for the provision of data (HIPC File No. 2007/2008-49). The results and conclusions are those of the authors, and no official edndorsement by Manitoba Health is intended or should be inferred. This article has been reviewed and approved by the members of the Manitoba Bone Density Program Committee. The analyses and conclusions in this report reflect the opinions of individual experts and not thier affiliated organizations.
Conflicts of interest
William Leslie is part of a speaker bureau for Merck Frosst and Amgen. He has also received unrestricted educational and/or research grants from Amgen; Merck Frosst; sanofi-Aventis; Procter & Gamble; Genzyme and is a member of the following advisory boards: Genzyme; Novartis; and Amgen. Lisa Lix received an unrestricted research grant from Amgen. In the past 3 years, Eugene McCloskey has received speaker fees and/or unrestricted research grants from Novartis, Amgen, AstraZeneca, Pfizer, Bayer, Procter & Gamble, Lilly, Roche, Servier, and Hologic.
Source of funding
The Canadian Multicentre Osteoporosis Study was funded by the Canadian Institutes of Health Research (CIHR), Merck Frosst Canada Ltd., Eli Lilly Canada Inc., Novartis Pharmaceuticals Inc., The Alliance for Better Bone Health: Sanofi-Aventis, Procter & Gamble Pharmaceuticals Canada Inc., Amgen, The Dairy Farmers of Canada and The Arthritis Society.
CaMos Research Group
David Goltzman (co-principal investigator, McGill University, Montreal), Nancy Kreiger (co-principal investigator, University of Toronto, Toronto), Alan Tenenhouse (principal investigator emeritus, Toronto), CaMos Coordinating Centre, McGill University, Montreal, Quebec: Suzette Poliquin (national coordinator), Suzanne Godmaire (research assistant), Claudie Berger (study statistician). Memorial University, St. John’s Newfoundland: Carol Joyce (director), Christopher Kovacs (co-director), Emma Sheppard (coordinator). Dalhousie University, Halifax, Nova Scotia: Susan Kirkland, Stephanie Kaiser (co-directors), Barbara Stanfield (coordinator). Laval University, Quebec City, Quebec: Jacques P. Brown (director), Louis Bessette (co-director), Marc Gendreau (coordinator). Queen’s University, Kingston, Ontario: Tassos Anastassiades (director), Tanveer Towheed (co-director), Barbara Matthews (coordinator). University of Toronto, Toronto, Ontario: Bob Josse (director), Sophie Jamal (co-director), Tim Murray (past director), Barbara Gardner-Bray (coordinator) McMaster University, Hamilton, Ontario: Jonathan D. Adachi (director), Alexandra Papaioannou (co-director), Laura Pickard (coordinator). University of Saskatchewan, Saskatoon, Saskatchewan: Wojciech P. Olszynski (director), K. Shawn Davison (co-director), Jola Thingvold (coordinator). University of Calgary, Calgary, Alberta: David A. Hanley (director), Jane Allan (coordinator). University of British Columbia, Vancouver, British Columbia: Jerilynn C. Prior (director), Millan Patel (co-director), Brian Lentle (radiologist),Yvette Vigna (coordinator).
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